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Will 3.5 EB exhaust fit Mustang 3.7?

Discussion in '2011-2014 V6 Mustang Tech' started by rehoward, Feb 21, 2020.

  1. rehoward

    rehoward New Member

    Jan 17, 2020
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    I have been unable to find a definitive answer to this question. Some say the 3.5 turbo exhaust drops right on and others say you need an adapter because the bolt pattern is different. One guy said you need to grind a bump off the cylinder head to get them to fit. And yet another guy said that appropriate heads can be found on some truck engines. So what is the real answer? These scattered answers are confusing me. Thanks
  2. 08'MustangDude

    08'MustangDude Profile Violation

    Jan 31, 2018
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    The exhaust does not bolt to the heads, it bolts to the exhaust manifolds/header pipes.
    SO, what are you asking, exhaust, or the manifolds and exhaust?
    Short answer is NO.

    They require a special spacer because the 3.7 Cyclone exhaust bolt pattern is different than the
    3.5 EcoBoost bolt pattern. You have to grind a bump off each 3.7 head so the 3.5 manifolds will fit.
    Still, you can find 3.7 heads that have the same bolt pattern that the Mustang 3.7 Cyclone engine
    does. Those 3.7s are used in trucks. The 3.7 Cyclone was made for higher end vehicles, and
    the Mustang, based on the Duratec motor.

    The EcoBoost manifolds won't even fit the 3.5 Duratec heads, same reason, different bolt

    I think there is an adapter plate out there, somewhere...